The Lindam Numi Aluminium Extending Safety Gate is one of the only ones which does not have a bar at the bottom which makes it safer at the to of the stairs. The cheapest price elsewhere I can find is £89.99. I know there are cheaper gates out there, but this seems to the be the best without the bottom bar.
Constructed from strong, yet lightweight aluminium, the Lindam Numi stair gate is easy to install and can be removed in seconds when not required thanks to its low profile wall mounting. The gate extends to fit openings between 63.5cm-106cm and has an extra wide walk-through with no step over bar. It features double-action locking for added safety and stability along with an anti-pinch hinge that prevents trapped fingers. With a patented ITS fine tuning system, the Numi stair gate provides a millimetre perfect fit. Upper and lower locking points give extra strength and rigidity over the gate's entire height, ensuring maximum immovability.